From d32a66b2a22df44ec11073b9d7b7cf9c130511cb Mon Sep 17 00:00:00 2001 From: Renato Botelho Date: Thu, 2 Jul 2015 17:30:59 +0000 Subject: [PATCH] When passwd or group information is changed (by pw, vipw, chpass, ...) temporary file is created and then a rename() call move it to official file. This operation didn't have any check to make sure data was written to disk and if a power cycle happens system could end up with a 0 length passwd or group database. There is a pfSense bug with more infor about it: https://redmine.pfsense.org/issues/4523 The following changes were made to protect passwd and group operations: * lib/libutil/gr_util.c: - Replace mkstemp() by mkostemp() with O_SYNC flag to create temp file - After rename(), fsync() call on directory for faster result * lib/libutil/pw_util.c - Replace mkstemp() by mkostemp() with O_SYNC flag to create temp file * usr.sbin/pwd_mkdb/pwd_mkdb.c - Added O_SYNC flag on dbopen() calls - After rename(), fsync() call on directory for faster result * lib/libutil/pw_util.3 - pw_lock() returns a file descriptor to master password file on success Differential Revision: https://reviews.freebsd.org/D2978 Approved by: bapt Sponsored by: Netgate --- lib/libutil/gr_util.c | 22 ++++++++++++++++++++-- lib/libutil/pw_util.3 | 3 ++- lib/libutil/pw_util.c | 2 +- usr.sbin/pwd_mkdb/pwd_mkdb.c | 25 ++++++++++++++++++++----- 4 files changed, 43 insertions(+), 9 deletions(-) diff --git a/lib/libutil/gr_util.c b/lib/libutil/gr_util.c index b0b0b36f0818..93b3eb2f92fc 100644 --- a/lib/libutil/gr_util.c +++ b/lib/libutil/gr_util.c @@ -141,7 +141,7 @@ gr_tmp(int mfd) errno = ENAMETOOLONG; return (-1); } - if ((tfd = mkstemp(tempname)) == -1) + if ((tfd = mkostemp(tempname, O_SYNC)) == -1) return (-1); if (mfd != -1) { while ((nr = read(mfd, buf, sizeof(buf))) > 0) @@ -318,10 +318,28 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) int gr_mkdb(void) { + int fd; + if (chmod(tempname, 0644) != 0) return (-1); - return (rename(tempname, group_file)); + if (rename(tempname, group_file) != 0) + return (-1); + + /* + * Make sure new group file is safe on disk. To improve performance we + * will call fsync() to the directory where file lies + */ + if ((fd = open(group_dir, O_RDONLY|O_DIRECTORY)) == -1) + return (-1); + + if (fsync(fd) != 0) { + close(fd); + return (-1); + } + + close(fd); + return(0); } /* diff --git a/lib/libutil/pw_util.3 b/lib/libutil/pw_util.3 index 706368fbffed..b558916c82d5 100644 --- a/lib/libutil/pw_util.3 +++ b/lib/libutil/pw_util.3 @@ -233,7 +233,8 @@ function returns 0 in case of success and -1 in case of failure. The .Fn pw_lock function locks the master password file. -It returns 0 in case of success and -1 in case of failure. +It returns a file descriptor to master password file in case of success +and -1 in case of failure. .Pp The .Fn pw_scan diff --git a/lib/libutil/pw_util.c b/lib/libutil/pw_util.c index befd1fb02d70..af749d5240de 100644 --- a/lib/libutil/pw_util.c +++ b/lib/libutil/pw_util.c @@ -226,7 +226,7 @@ pw_tmp(int mfd) errno = ENAMETOOLONG; return (-1); } - if ((tfd = mkstemp(tempname)) == -1) + if ((tfd = mkostemp(tempname, O_SYNC)) == -1) return (-1); if (mfd != -1) { while ((nr = read(mfd, buf, sizeof(buf))) > 0) diff --git a/usr.sbin/pwd_mkdb/pwd_mkdb.c b/usr.sbin/pwd_mkdb/pwd_mkdb.c index 69a2faefa8e7..c382cb5a5e24 100644 --- a/usr.sbin/pwd_mkdb/pwd_mkdb.c +++ b/usr.sbin/pwd_mkdb/pwd_mkdb.c @@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include #include @@ -227,14 +228,14 @@ main(int argc, char *argv[]) clean = FILE_INSECURE; cp(buf2, buf, PERM_INSECURE); dp = dbopen(buf, - O_RDWR|O_EXCL, PERM_INSECURE, DB_HASH, &openinfo); + O_RDWR|O_EXCL|O_SYNC, PERM_INSECURE, DB_HASH, &openinfo); if (dp == NULL) error(buf); clean = FILE_SECURE; cp(sbuf2, sbuf, PERM_SECURE); sdp = dbopen(sbuf, - O_RDWR|O_EXCL, PERM_SECURE, DB_HASH, &openinfo); + O_RDWR|O_EXCL|O_SYNC, PERM_SECURE, DB_HASH, &openinfo); if (sdp == NULL) error(sbuf); @@ -291,13 +292,13 @@ main(int argc, char *argv[]) method = 0; } else { dp = dbopen(buf, - O_RDWR|O_CREAT|O_EXCL, PERM_INSECURE, DB_HASH, &openinfo); + O_RDWR|O_CREAT|O_EXCL|O_SYNC, PERM_INSECURE, DB_HASH, &openinfo); if (dp == NULL) error(buf); clean = FILE_INSECURE; sdp = dbopen(sbuf, - O_RDWR|O_CREAT|O_EXCL, PERM_SECURE, DB_HASH, &openinfo); + O_RDWR|O_CREAT|O_EXCL|O_SYNC, PERM_SECURE, DB_HASH, &openinfo); if (sdp == NULL) error(sbuf); clean = FILE_SECURE; @@ -721,13 +722,27 @@ void mv(char *from, char *to) { char buf[MAXPATHLEN]; + char *to_dir; + int to_dir_fd = -1; - if (rename(from, to)) { + /* + * Make sure file is safe on disk. To improve performance we will call + * fsync() to the directory where file lies + */ + if (rename(from, to) != 0 || + (to_dir = dirname(to)) == NULL || + (to_dir_fd = open(to_dir, O_RDONLY|O_DIRECTORY)) == -1 || + fsync(to_dir_fd) != 0) { int sverrno = errno; (void)snprintf(buf, sizeof(buf), "%s to %s", from, to); errno = sverrno; + if (to_dir_fd != -1) + close(to_dir_fd); error(buf); } + + if (to_dir_fd != -1) + close(to_dir_fd); } void